我的经验my drain pipe was cut once by a plumber to do a snake out. I bought a mechanical snake later, however, it can not go far as hand is not as powerful as electrical snake.
There is a screw nut on the drain just above the basement floor in my case. To pour Drano there is much effective than from sink, as Drano is basically a gel and has to travel (with huge loss on the way) to the spot blocked.
Good luck.
-auser(a user);
2010-5-7{406}(#6055675@0)